rear wheel cylinder rebuild kit , hard or soft boot ?

Why waste your time when you can buy the whole thing for $5 .
More Information for RAYBESTOS WC37235

thats the back up plan , but when i did the fronts , both brake lines broke trying to get them off and stripped two of the wheel cylinder bolts as well . ( even after soaking everything in pb blaster once a day for about four days ) since the back is even rustier than the fronts , i was gonna try to just rebuild the old ones without taking them off .